A contact lens photostimulator for surgical monitoring

A haptic contact lens stimulator has been developed to allow monitoring of the visual evoked potential to flash stimulation during orbital surgery. The contact lens stimulator is fitted with a small plastic prism into which a fibre-optic cable is inserted at right angles to the axis of the contact lens. This allows both the stimulator and the fibre-optic to be permanently in place throughout orbital surgery without interfering with the surgeon's vision or dexterity. Using this technique continuous evoked potentials can be obtained allowing immediate feedback to the surgeon of any condition threatening the integrity of the optic nerve. The technique has now been used on over 20 eyes and is commercially available.